Composition of stainless iron alloy



Patented Dec. 2i, 19 525. i

nnirnn nausea MASAAKI YDNEZU', 01E TOKYO FU, AND EITARO ENDO, F TOKYO, JAEAN.

COMPOSITION OF STAINLESS IRON ALLOY.

No Drawing.

This invention relates to a composition of a stainless iron alloy consisting in adding to chromium steel from 1 to" of Vanadium, and the object thereof is to chan e the 5 physical properties of various kinds, 0 high chromium steel and make them soft and malleable. y

\ Various kinds of high chromium steel, say

I those containing from 8 to 30% of chromi- W um have all of them the following properties ' 1. Asproperty to be hardened even in the air, that is if a high chromium steel is heated to red'heat and allowed to cool in the air,

without suddenly cooling it in water or oil,

it becomes hardened. I

Of course this property difiers in degree according to kinds of such steel. For instance, in chromium steel having greater percentage 6f chromium or somewhat greater percentage of nickel, this property is not so conspicuous;

2. A high hardness, even if a high chromium steel isthoroughly annealed, it cannot be made as soft as annealed common carbon steel. Consequently, the work to be done in red heat is more diflicult with it than with common carbon steel;

3 turning it in a lathe. If a high chromium steel thoroughly annealed is scraped or turned in a lathe, the cutting tool harder than the chromium steel soon becomes worn andbroken at its edge, and y 4. Diificulty of bending in the atmospherictemperature. elf you bend high chromium steel at atmospheric temperature, it will become broken or cracked. Even if it is thoroughly annealed, it can only be bent to a 40 slight curvature.

Common high chromium steel having such properties cannot be madeinto ornamental articlesof delicate workmanship. It is. also impossible to draw such steel into fine wire or roll same into thin sheets. But if a suitable lpercentage ofvanadium'is added to it,

it w' p 1. Lose its property ofbecoming hardened, not only in the air. but even if it is sub"- jected to an ordinary hardening process,

such as heatingthemetalto 1000 C. or more -,and suddenly cooling1 same in water, it will not become hardene Consequently, there is no need of annealing ,such steel.

Application filed a ru 2a, 1924. Serial no. 708,586.

2. Become soft, high chromium steel unannealed but containing vanadium being softer'than high chromium steel containing" no vanadium but annealed, tlius decreasing the 'difii'culty of the work of scraping, turning1 in a lathe, and working the steel heated, an

8. Become flexible at atmospheric temperatures, high chromium steel unannealed but containing vanadium being far more flexible than'high chromium steel annealed but containing no vanadium.

It may here be noted that the softness and the property of flexibility are not, evidently, the result of the steel losing its property of becoming hardened.

The above properties are not apparent if the proportion of vanadium is less than 1%,

but'become apparent gradually as the proportion increases, and being most evident when the proportion of vanadium is e or 5% w g Moreover, the properties, do not become stronger even if the proportion of vanadium is increased, but on the contrary too much vanadium has injurious effects on the alloy. Consequently the proportion of vanadium a should-not exceed 10%. ()f'course the ef- 3. Difiiculty in the work of scraping it"fir fects of the addition of vanadium are difi'ercut for different kinds of steel,.but for ex Y ample an alloy whose composition is Gr. 13%, V. 4% and G. O. 3%, the remainder being iron, the hardness has been found to be- 7 by Brinelly test of hardness, it being the same whether the alloyis subjected to hardening or to annealing processes, and as to fiexib1lity,-the steel can be bent without cracks. i

The efiects of carbon on the physical properties of steel is stronger and more ap parent in high chromium steel than in com 9 mon carbon steel, but if a suit-able proportion of vanadium is added thereto, the quantity of carbon contained has no efl'ect on the physical properties of the alloy.

The following is an example of carrying my-invention into efl'ect:

Melt iron in a furnace and add. thereto chromium, or ferro-chrbmium previously measured. When the two have become perfectly fused, add thereto a suitable quantity 105 of ferro-vanadium. Vanadium in the molten state oxidizen quickly and floats in the molten mass. Therefore the molten mass in the furnace must be poured quickly into a mold percent of 'ehr'omium and 1 to 10 percent of as soon as it attains a, suitable degree of; vanadium, the remainder being iron. fusion. r

I In testimony whereof we have signed our 1 In this invention, there is no harm in add- 11 '8 ing nickel or any metal We claimz. MASAAKI YONEZU. A stainless iron alloy consisting of 8 to 30 EITARG ENDO.

ames to this specification. besides vanadmrn. 

